Nacho Monreal, left, and Laurent Koscielny can do nothing as Arsenal go 5-0 down at Liverpool on Saturday. Photograph: Tom Jenkins for the Guardian

Arsène Wenger accepts that Arsenal's season is on a knife edge after their heavy defeat at Anfield last Saturday. They face a pivotal week which has the potential to make or break their campaign, with an FA Cup tie against Liverpool and a Champions League duel against Bayern Munich following hot on the heels of Manchester United's Premier League visit on Wednesday night.

Three competitions are on the line. In recent seasons Arsenal have been derailed when a cluster of high-profile games with different honours at stake hurtles into their path, and Wenger understands why there are doubts about whether they can overcome the tendency to implode.

"It's normal that people raise this kind of question," the manager said. "But we have always maintained a certain level. We have lost some championships, we have won as well some championships when the others lost it. The professionalism of the players? I have guarantees that they will give their best until the end of the season. If somebody is better than us, we have to accept it. But at the moment we are in a very interesting position and it is a long way to go.

"Two weeks ago, Manchester City were unstoppable, so it changes quickly. Everybody plays Champions League, so everybody can drop points. It is just down to our belief and how well we respond."

With no developments on the injury front (although Yaya Sanogo, the raw young striker signed last summer, is finally fit he is unlikely to feature) Wenger does not have the option of sweeping changes to try to shake his team up in reaction to losing 5-1 at Anfield. He often relies on Tomas Rosicky for the highest-profile challenges, so the Czech midfielder may come into the side. But otherwise Manchester United can expect a similar lineup to the one lacerated by Liverpool.

"I can make one or two changes but the core of the team has to be exactly the same," Wenger said. "After a big disappointment like that you always sit there thinking: 'Do I make five or six changes or do I give them a chance to show it was just an accident?' And most of the time you give the players a chance, especially if they have done well before. If there is a continuity of a bad patch you have to change things but, if it is just one game, most of the time you give the players a chance to respond.

"It is always a disappointment to lose a game but I think it was an accident because we have been very stable defensively and we have to treat it like that. We have just been on a 10-game unbeaten run. You cannot consider one game as the trend, the pattern of our season. A successful season is decided by how you respond."